2009-2010年冬季南海东北部中尺度过程观测

根据南海北部陆架陆坡海域2009-2010年冬季航次的CTD调查资料,发现西北太平洋水在上层通过吕宋海峡入侵南海,其对南海东北部上层水体温盐性质的影响自东向西呈减弱趋势,影响范围可达114°E附近。入侵过程中受东北部海域反 气旋式涡旋(观测期间,其中心位于20.75°N,118°E附近) 的影响,海水的垂向和水平结构发生了很大变化,特别是涡旋中心区域,上层暖水深厚,混合层和盐度极大值层显著深于周边海域。该暖涡在地转流场、航载ADCP观测海流及卫星高度计资料中均得到了证实。暖涡的存在还显著影响了海水化学要素的空间分布,暖涡引起的海水辐聚将上层溶解氧含量较高的水体向下输运,使次表层的暖涡中心呈现高溶解氧的分布特征。

Mesoscale observation in the northeast South China Sea during winter 2009-2010

According to the obtained CTD data of northern South China Sea (SCS) shelf and slope area during the winter cruise in 2009-2010, it found that the northwest pacific water intruded into SCS in the upper layer through Luzon Strait, its effect on tempearture and salinity of northeastern SCS upper layer water decreased from east to west and extended up to about 114°E. Due to the effect of anticyclone eddy in the northeastern SCS during intrusion processing, the vertical and horizontal structure of water mass changed remarkably, especially in the center erea of eddy, the depth of mixed layer and salinity maximum layer is evidently deeper than the surrounding area. The warm eddy was confirmed from the geostrophic current, ADCP current and satellite altimeter data. The existence of warm eddy also affacted the spacial diffusion of chemistry elements markedly. Due to the water convergency caused by warm eddy, the upper layer water with higher concentration dissolved oxygen was transported downwards which induced higher concentration dissolved oxygen existing in the center of warm eddy in upper layer.